EPI distortion using T1

[Diego Cardoso Fragoso]

Hello dear friends!

I'm using de original T1 to correct the EPI distortion. I strict followed the DTI manual for this purpose but there are some data that looks I little bit strange.

This is what I have done so far:

- Convert Bval and Bvec to B-matrix.

- Convert DWI .nii file to readable .mat file. (changed the permute gradient components [y x z] and the flip sign of gradient components (x y -z) so that the DEC map looks normal). Matriz size 128 128 67. Number of DWI images (32).

- Flip dimensions of T1-weighted image (Default settings: permute dimensions: 1 2 3 & Flip dimensions: 0 0 0)

- Mask background of T1-weighted image (Kernel size: 3 Threshold: 0.02)

- Crop size

- Activated EPI correction in settings (“Yes- to do the EPI correction (non rigid)” and chosen masked the T1w image.

- More settings: Type of registration: “FA” Deformation axes: “1 0 0”

I have I question. Do the T1 and DWI have to have the same matrix?

Thank you in advance!

Sincerely,

Diego

[Diego Cardoso Fragoso]

I attached this example. The upper frontal lobes are distorted!